Analysis of the Impact of Galileo Observations on the Tropospheric Delays Estimation

In this study we present analysis of the impact of Galileo observations on the ZTD and tropospheric gradients estimation. The tropospheric parameters were obtained in various scenarios, which differ from each other only in used satellite systems: Galileo-only, GPS-only, GPS/Galileo, GPS/GLONASS and GPS/GLONASS/Galileo. Then, comparative analysis between Galileo-only solution and the other ones, was carried out. As a reference, the combined EPN solution was adopted. Analysed period covers two time spans: one year (02.2016 – 01.2017) and nearly EOC (10.2016-01.2017). Results shows standard deviation of Galileo solution at the level of 6 mm (w.r.t. reference solution), which is higher than the other ones. However, adding a Galileo observations can cause decreasing of solution standard deviations, which lead to the higher quality. A positive impact of new standard of antennas calibrations (IGS14) on Galileo ZTD bias standard deviation was also noticed. At the end some discussion about gradients estimation are presented.